Indirectly as a tax monitoring tool, with non-cash transactions, the possibility of tax avoidance will also be smaller. Why? Non-cash transactions make more money deposited in banks than elsewhere. Thus, tax avoidance is increasingly difficult.
Capital controls may be part of the rationale too:
Malaysia central bank governor wants option of capital controlsThey want to pull cash out of circulation. It's too easy to smuggle out of the country and dump on the offshore forwards markets, which is exactly what the central bank is afraid of. They are becoming increasingly worried about a financial crisis and the associated effects on the Ringgit.